Originally Posted by kjjohny1991
tried re installing firefox as well but did not help
Have you done any modifications to gnome? If you have, you could try setting it to default with the following command (NOTE: this will erase all of your personal settings). Press Alt + F2 ant type:
rm -rf .gnome .gnome2 .gconf .gconfd .metacity .cache .dbus .dmrc .mission-control .thumbnails ~/.config/dconf/user ~.compiz*
There is a big chance this will not work but it's worth of trying.
After you do this, log out and log back in... Now go to extensions.gnome.org and try few of those extensions